Software applications typically interact with a user by posing a query and then receiving a user's response. Some software must always exist on the user's computer to perform this task, even if the application that the user is interacting with exists in the network. For example, consider a network-resident telephony service that prompts a called party at his or her computer to choose a phone to direct an incoming call to. Some software must reside on the called party's computer to convey the prompt from the network to the user and then convey the user's response back to the network. The problem is that one would like to avoid mandating that all users of a service install, run, and maintain specialized software on their computer to convey queries and responses between the user and network-resident services. However, any general solution to this problem should desirably ensure that it supports the bulk of the anticipated classes of user interaction, and also must be extensible enough for use by many applications.